A structure in which a bar handle is fixed to a chassis by bolting or welding is commonly used in, e.g., weed cutters and other work machines. Recently, a technique for detachably mounting the bar handle to the chassis has often been used to accomplish this, and one example of this technique is a pipe handle holding structure. The pipe handle holding structure is often used in work machines that are operated by an operator grasping the bar handle. Weed cutters which use this type of pipe handle holding structure are known as disclosed, e.g., in Japanese Patent Application Laid-Open Publication No. 2002-218813 (JP 2002-218813 A).
In the pipe handle holding structure disclosed in JP 2002-218813 A, an external peripheral surface of a round pipe-shaped bar handle is held by a holder. In other words, the bar handle is held by a holder provided to a chassis of a work machine. To be more specific, the holder is comprised of a pair of halved parts. The divided parts have respective grooves for covering the external peripheral surface of the round pipe-shaped bar handle. The bar handle is fitted into the grooves and the holder halves are assembled and fastened together, whereby the holder halves hold the external peripheral surface of the bar handle therebetween. Thus, the bar handle is held by the holder, using the friction force between the internal peripheral surfaces of the grooves and the external peripheral surface of the bar handle.
In this type of pipe handle holding structure described above, a large fastening force is needed to ensure that the bar handle does not slip in the holder. Therefore, a tool is used to firmly fasten the fastening bolts. This is sufficient in cases in which the bar handle is attached to and detached from the holder infrequently.
However, in cases in which the bar handle is attached to and detached from the holder frequently, the attaching/detaching operation is troublesome and has room for improvement. One example of a case of frequent attaching and detaching the bar handle to and from the holder is a case of changing the angle at which the bar handle is held on the holder along with a change in the work specifications of the work machine. Another example is a case in which the angle at which the bar handle is held on the holder is changed between a usage state and a storage state of the work machine.
To prevent slipping between the holder and the bar handle, it has been proposed that serrations or other irregularities be provided to both the internal peripheral surfaces of the grooves of the holder and the external peripheral surface of the bar handle. Because of this assembled structure using irregularities, a small fastening force from the fastening bolts is sufficient. However, in cases in which the bar handle is attached to and detached from the holder frequently, there is further room for improvement in order to ensure that the irregularities will be durable.